Replace $(cat file) invocations with $(< file) for better performance

Author: Oliver Weiler

src/main/bash/sdkman-availability.sh

@@ -75,11 +75,11 @@ function __sdkman_update_broadcast() {
 	broadcast_old_id=""
 
 	if [[ -f "$broadcast_id_file" ]]; then
-		broadcast_old_id=$(cat "$broadcast_id_file")
+		broadcast_old_id=$(< "$broadcast_id_file")
 	fi
 
 	if [[ -f "$broadcast_text_file" ]]; then
-		BROADCAST_OLD_TEXT=$(cat "$broadcast_text_file")
+		BROADCAST_OLD_TEXT=$(< "$broadcast_text_file")
 	fi
 
 	if [[ "$SDKMAN_AVAILABLE" == "true" && "$broadcast_live_id" != "$broadcast_old_id" && "$COMMAND" != "selfupdate" && "$COMMAND" != "flush" ]]; then

src/main/bash/sdkman-cache.sh

@@ -18,13 +18,13 @@
 
 function ___sdkman_check_candidates_cache() {
 	local candidates_cache="$1"
-	if [[ -f "$candidates_cache" && -n "$(cat "$candidates_cache")" && -n "$(find "$candidates_cache" -mmin +$((24 * 60 * 30)))" ]]; then
+	if [[ -f "$candidates_cache" && -n "$(< "$candidates_cache")" && -n "$(find "$candidates_cache" -mmin +$((24 * 60 * 30)))" ]]; then
 		__sdkman_echo_yellow 'We periodically need to update the local cache. Please run:'
 		echo ''
 		__sdkman_echo_no_colour '  $ sdk update'
 		echo ''
 		return 0
-	elif [[ -f "$candidates_cache" && -z "$(cat "$candidates_cache")" ]]; then
+	elif [[ -f "$candidates_cache" && -z "$(< "$candidates_cache")" ]]; then
 		__sdkman_echo_red 'WARNING: Cache is corrupt. SDKMAN cannot be used until updated.'
 		echo ''
 		__sdkman_echo_no_colour '  $ sdk update'